[urn] Registration for `c2pa` URN

[Leonard Rosenthol <[e-mail]>]

Namespace Identifier:  c2pa

Version:  1

Date:  2024-07-30

Registrant:
Leonard Rosenthol, on behalf of C2PA (Coalition for Content Provenance and Authenticity)
[e-mail]<mailto:[e-mail]>, 1-215-808-4978

Purpose:

Each C2PA Manifest (aka Content Credential) created to incorporate provenance information about a given asset is given a unique identifier which has historically been an incorrectly formatted UUID URN.  This proposal, in conjunction with an updated specification, will define a new `c2pa` URN syntax for this purpose.

The `c2pa` URN will consist of a UUID URN (as per RFC 9562) with additional information, specific to C2PA added.  These URNs are non-resolvable, simply serving as unique identifiers. In this way, the ability to unambiguously compare them is of significant importance.

Syntax:

A `c2pa` URN shall consist of two mandatory and two optional components, in the following order, with `:`'s between each section.

                - URN identifier (`urn:c2pa`): REQUIRED
                - UUID v4, in string representation (as per RFC 9562, section 4): REQUIRED
                - Claim Generator identifier string : OPTIONAL
                - Version and Reason string (as described below) : OPTIONAL

When present, the "Version and Reason" string shall consist of a `v` followed by a monotonically increasing integer, starting with 1, followed by an underscore (`_`) and then an integer representing the reason for the re-labeling.

EXAMPLES:

                - `urn:c2pa:F9168C5E-CEB2-4FAA-B6BF-329BF39FA1E4`
                - `urn:c2pa:F9168C5E-CEB2-4FAA-B6BF-329BF39FA1E4:acme`
                - `urn:c2pa:F9168C5E-CEB2-4FAA-B6BF-329BF39FA1E4:acme:v2_1`


Assignment:

URNs conforming to this scheme are self-assigned, based on the creation of the UUID (as per RFC 9562) and the optional inclusion of the Claim Generator identifier string and Version and Reason.


Security and Privacy:

No known security or privacy issues exist.


Interoperability:

A standard UUID URN can be "losslessly upgraded" to a `c2pa` UUID, if there were to exist a workflow that required doing so.  Beyond that, no known concerns or requirements around interoperability exist.

Resolution:  N/A

Documentation:  https://c2pa.org/specifications/specifications/2.1/specs/C2PA_Specification.html

NOTE: Version 2.1 is not yet published but will contain this documentation when published

Additional Information:  NONE

Revision Information:  N/A